In the past, paper sheets contained in an Automated Teller Machine (ATM) and the like are contained in a housing of an ATM cassette and the like taken out from the Automated Teller Machine and the like. In the past, a person such as an operator has to manually count the paper sheets contained in the housing of the ATM cassette and the like.
Therefore, it used to be required to efficiently process the paper sheets contained in many housings (cases) collected from the Automated Teller Machine and the like.